Spectroscopic ellipsometry and reflective spectroscopy are powerful tools in the characterization of materials at interfaces that are used in technologies such as nanotechnology, biotechnology, and photocell fabrication. Silicon or other wafers with no coating have been used extensively as the substrate for ellipsometry and IR spectroscopy and oxide coated wafers already exist in market, but using the wafers with specific oxide thicknesses to achieve optimal or near optimal signals for ellipsometry and IR spectroscopy for a specific specimen type, does not exist. This invention relates to the application of non-absorptive auxiliary layers (coatings) with specific thicknesses and optical constant, to a wafer or a substrate (collectively referred to as the substrate layer) to amplify the reflective signal at a given wavelength of interest.